We've landed rovers there. We've drilled holes into its rocks. We've even scooped up its soil and studied it to the most finite particle.
But when are we finally going to put our own footprints on Mars?
President Obama says we'll get a human to the Red Planet by 2030, but this isn't the first time a mission like this was mulled by the United States. The world has wondered what's next for humans in space ever since Neil Armstrong set foot on the moon in 1969. It only seems natural to look to our celestial neighbor for our next adventure — and now people outside of NASA are vying for that ultimate journey.
We will put a human on Mars eventually. The real question is who will do it first.
The Mars Society has pushed for a manned mission to the fourth planet since the early 1990s. It continues to be one of the most influential advocacy groups for the idea because it operates — oftentimes behind the scenes — of other commercial and government Mars endeavors. It doesn't hurt that it's headed up by Robert Zubrin, an eccentric aerospace engineer who worked with a small team in the 1990s to create a detailed plan for NASA that outlined a way to get humans to Mars in a cost-effective way.
When NASA turned down the proposal, Zubrin turned it into a book, called The Case For Mars, and the Mars Society was born. Today, it has an almost cult-like following of hundreds of volunteers around the world who spread the word about manned missions to Mars.
But what sets the Mars Society apart from any other private endeavor is its research stations. The organization built its Flashline Mars Arctic Research Station inside a giant crater on Devon Island, which is about 100 miles north of Resolute in Nunavut, Canada. Crews from around the world — a mix of scientists, engineers and journalists — live in the station for extended periods of time, conducting experiments as though they're on Mars.
A more accessible twin sister, the Mars Desert Research Station, is located in Hanksville, Utah. Starting in late fall and going through early spring, crews live in the remote, two-story station for two-week intervals. They simulate a true Mars mission, from not leaving the habitat without wearing a spacesuit, to maintaining little to no communication with the outside world.

The remote Mars Desert Research Station in Hanksville, Utah.
Image: Amanda Wills, Mashable Amanda Wills, Mashable
Though it's not perfect — they are in 100% gravity, after all — Zubrin hopes that these stations will inspire NASA to do similar projects for its future Mars astronauts.
“I would like nothing better than for NASA to copy us and say, ‘Okay, we see what you're trying to do here, but your simulation is primitive. We can do this much more realistically. Step aside,'" Zubrin said. "Then they can leave us behind."
The biggest technical hurdles to getting humans on Mars are landing a vehicle — the two-ton Curiosity rover is the heaviest thing we've sent to Mars — and taking off once the astronauts are ready to come home.
Dutch entrepreneur Bas Lansdorp thinks he has a solution to the latter problem: a one-way mission. He started Mars One a few years ago to find the first crew of people willing to live out the rest of their lives on another planet in the first human colony. Then every few years, Mars One would send more crews to populate the colony and replenish resources.
In a marketing blitz over the past year, Lansdorp has touted his campaign and called for applicants. The only requirement to be on the crew? You must be 18 years old. The rest you can learn in training over the next eight years, before launching to the Red Planet in 2023. So far, hundreds of thousands of people have applied to Mars One, and the pool has been narrowed down to 1,058.
There are the extreme technical difficulties that Lansdorp never seems to address — he claims he'll use SpaceX technology, but a SpaceX spokesperson told us no partnership is in the works. Thus, he'll have to fund the venture. By his calculations, Lansdorp needs $6 billion for the first mission, seemingly a bargain when you consider NASA's Curiosity rover cost $2.5 billion.
However, Lansdorp has a business plan. He'll turn the mission into one big reality television show that the whole world will watch. And with billions of viewers, advertising and sponsorship dollars should come easy, right? That's what Lansdorp is banking on, at least.
So far, Mars One received some funding from Lockheed-Martin, but Lansdorp repeatedly says he will not partner with federal space agencies like NASA to make this happen.
What do you get a multimillionaire who already has everything, including a trip to space? For Dennis Tito, the next big thing is a quick spin around Mars.
Though the American engineer was the very first space tourist in 2001, Tito won't be going on this Martian vacation. Instead, he formed Inspiration Mars and is looking for an adventurous married couple to go on a privately financed spaceflight to the planet by 2018. The crew wouldn't land, they'd only circle the planet.

Dennis Tito, then 60, shortly after his landing in 2001, completing his multimillion dollar cosmos adventure.
Image: Mikhail Metzel/Associated Press
Tito says the biggest concern is the grueling journey, which would take more than 500 days and wreak havoc on even the fittest of bodies due to the extended time in zero gravity.
Tito hired a group of scientists and engineers to plan out the mission and account for major risks, including both mental and physical health. They found that one of the biggest challenges will be that isolation, which is how Tito arrived at the idea of sending a married couple. They'll already know they can stand to be around each other for an extended period of time.
Like Mars One, Tito's team proposes using SpaceX's Dragon space capsule to get to Mars, although the private space company has yet to run any test flights with humans on board.
Tito's plan is grandiose indeed, and he even admitted in November that it was probably impossible without significant support and funding from NASA. But never count out a guy who paid for his own roundtrip ticket to space.
Who do you think will get to Mars first? Tell us in the comments.